1.) They can automatically qualify by winning their conference tournament title or, in the case of the conferences that don't have conference touraments such as the Ivy League, they can qualify by winning their conference's regular season title.
2.) By having a high enough RPI to get one of the 33 at-large bids. The RPI considers the team's record and their performance against quality (or not-so-quality) opponents.
3.) By not getting caught violating the NCAA rules.
The NCAA Tournament and The NIT tournament
NORTH CAROLINA TARHEELS - 100
The Kentucky Wildcats won the NCAA basketball tournament in 1948.
Teams that are on the verge of being in or out of the NCAA tournament.
Texas had the most this year
About 20 million Tunchi!! :)
The original NCAA Division 1 College Basketball Tournament 1939 field consisted of 8 teams.